Function startBoundedSource

packages/core/src/runtime/webAudioTransport.ts:33–57

* Start a buffer source, bounding it to the clip's authored window * (`data-duration`) so a trimmed clip stops at its edge instead of running the * buffer to the source file's natural end. `clipSourceLen` is the clip span in * buffer seconds; the third `start()` arg is the portion to play from th

(
  node: AudioBufferSourceNode,
  opts: {
    elapsed: number;
    mediaStart: number;
    scheduledAt: number;
    safeRate: number;
    clipDuration: number;
  },
)

 * play); the caller should discard the source.
 */
function startBoundedSource(
  node: AudioBufferSourceNode,
  opts: {
    elapsed: number;
    mediaStart: number;
    scheduledAt: number;
    safeRate: number;
    clipDuration: number;
  },
): boolean {
  const { elapsed, mediaStart, scheduledAt, safeRate, clipDuration } = opts;
  const hasBound = Number.isFinite(clipDuration) && clipDuration > 0;
  const clipSourceLen = clipDuration * safeRate;
  if (elapsed >= 0) {
    const remaining = clipSourceLen - elapsed;
    if (hasBound && remaining <= 0) return false;
    if (hasBound) node.start(0, elapsed + mediaStart, remaining);
    else node.start(0, elapsed + mediaStart);
    return true;
  }
  const delay = -elapsed / safeRate;
  if (hasBound) node.start(scheduledAt + delay, mediaStart, clipSourceLen);
  else node.start(scheduledAt + delay, mediaStart);
  return true;
}

export type ScheduledSource = {
  el: HTMLMediaElement;